CHAPTER XXIII 



ISOLATION OF UNKNOWN BACTERIA FROM A 

 MIXTURE 



1. Make hanging-drop, stained, and Gram prepara- 

 tions from the mixture. Note observations and results. 



2. Melt five or six agar-tubes, and cool to 43. 



3. Transfer 5 or 6 loopfulsof the mixture to a tube 

 of liquid agar, from this to a second, and so on until all 

 the melted tubes are inoculated. 



4. Pour into sterile Petri dishes, and mark them with 

 successive numbers and the date. Place in the thermo- 

 stat. 



5. After 24 hours examine the colonies under the 

 low power, describe them in the usual manner, and 

 transfer to agar-slants all those which show different 

 appearances. 



6. Now proceed with the usual routine study. Make 

 hanging-drop, stained, and Gram preparations, transfer 

 to all the media, and describe the culture characteristics 

 accurately. Make sketches in the usual manner. 



7. Special tests may become necessary after 24 or 

 48 hours. Such tests may consist of 



Capsule stain. 



Spore stain. 



Stain for acid-resisting bacilli. 



Fermentation tests of all those which produce gas 

 in glucose-agar. Also note the growth, or lack of growth, 

 in the closed arm of the fermentation-tube. 



Test for acid in neutral broth. 



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